From ef91d3d6a4c39421fd3a391e02cd82f9f3aee4a8 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 29 Sep 2014 22:52:41 +0800 Subject: [PARSER] Handle backslash newlines properly after dollar sign On Tue, Aug 26, 2014 at 12:34:42PM +0000, Eric Blake wrote: > On 08/26/2014 06:15 AM, Oleg Bulatov wrote: > > Hi! > > > > While playing with sh generators I found that dash and bash have different > > interpretations for sequence. > > > > $ dash -c 'EDIT=xxx; echo $EDIT\ > >> OR' > > xxxOR > > Buggy. > > > $ bash -c 'EDIT=xxx; echo $EDIT\ > > OR' > > /usr/bin/vim > > Correct behavior. > > > > > $ dash -c 'echo "$\ > > (pwd)"' > > $(pwd) > > > > Is it undefined behaviour in POSIX? > > No, it's well-defined, and dash is buggy. POSIX says: > > http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_03 > > "the shell shall break its input into tokens by applying the first > applicable rule below to the next character in its input" > > Rule 4 covers backslash handling, while rule 5 covers locating the end > of a word to be subject to $ expansion. Therefore, rule 4 should happen > first. Rule 4 defers to the section on quoting, with the caveat that > joining is the only substitution that happens immediately as > part of the parsing: > > http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02 > > "If a follows the , the shell shall interpret this > as line continuation. The and shall be removed > before splitting the input into tokens. Since the escaped is > removed entirely from the input and is not replaced by any white space, > it cannot serve as a token separator." > > So the fact that dash is treating the elided backslash-newline as a > token separator, and parsing your input as if ${EDIT}OR instead of > ${EDITOR} is a bug in dash. I agree. This patch should resolve this problem and similar ones affecting blackslash newlines after we encounter a dollar sign. Signed-off-by: Herbert Xu --- ChangeLog | 1 + 1 file changed, 1 insertion(+) (limited to 'ChangeLog') diff --git a/ChangeLog b/ChangeLog index 0fbc514..398bd15 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,6 +1,7 @@ 2014-09-29 Herbert Xu * Kill pgetc_macro. + * Handle backslash newlines properly after dollar sign. 2014-09-28 Herbert Xu -- cgit 1.4.1